There are luxurious cars, and there are fuel-efficient cars. There are even some that offer moderate levels of both characteristics. But no vehicle has managed—or even attempted—to take luxury and fuel economy simultaneously to such high levels as has the 2010 Lexus HS250h, the industry’s first dedicated luxury hybrid.

From the start Lexus has earned a reputation for well-sorted ergonomics, and the HS carries on this fine tradition. Logically sized and arranged knobs and buttons handle most functions. Secondary settings and the nav system are operated, as in the RX, via Lexus’s response to iDrive.

The HS 250h is the Lexus brand’s first dedicated hybrid, just as the Prius was for its parent brand Toyota. Previous Lexus hybrids were adaptations of existing vehicles, including the popular RX 400h crossover—replaced for 2010 by the RX 450h—the GS 450h sports sedan, and the full-size luxury barge LS 600h. But the HS will be sold just as a hybrid, with no gasoline-only version.

A comfortable palmrest, force-feedback, and slick graphics provide the console-mounted toggle pad with much of the familiar feel of a computer mouse. An available 15-speaker Mark Levinson system provides another sign that the HS isn’t a Toyota anymore.

The HS 250h shares its 147+40-horsepower powertrain with the Toyota Camry Hybrid. Rough engine, ropy CVT, non-linear power delivery, non-linear brakes…a whole lot of not good.

And the 2.4-liter gas-hybrid four-cylinder sounds and feels almost normal in regular driving. There’s some scoot off the line, thanks to the assistance provided by the insta-torque electric motor. Acceleration slackens at higher speeds, but never becomes downright slow. Force the engine up towards the assumed redline, and you’ll escape a four-cylinder Sonata, if not the four-cylinder sonata.